Power-driven hack saw



July 7, 1925.

1,545,454 D. H. POWELL POWER DRIVEN HACK SAW Filed March 21, 1924 .Z7.H.Powell (2 INVENTUR ATTORN EY Patented July 7, 1925.

UNITED STATES PATENT OFFICE.

Application filed March 21, 1924. Serial No. 700,908.

To all whom it may concern:

Be it known that I, Doom H. POWELL, a citizen of the United States, residin at Norris, in the county of Madison and tate of Montana, have invented new and useful Improvements in Power-Driven Hack Saws, of which the following is a specification.

This invention relates to saws and has for its object the provision of a novel hack saw provided with electric motor means for imparting reciprocatory movement to the blade, the device being capable of manual movement at the same time so as to effect rapid cutting with very little effort on the part of the user.

An important and more s ecific object is the provision of a device 0 this character equipped with spring means normally drawing the blade in one direction this means assisting movement of the blade and being, moreover, adjustable so that the tension may be varied.

An'additional object is the provision of a device of this character which will be simple and inexpensive in manufacture, easy to use, positive in action, efiicient and durable in service and a general improvement in the art.

With the above and other objects and advantages in view the invention consists in the details of construction to be hereinafter more fully described and. claimed and illustrated in the accompanying drawings, in which:

Figure 1 is a side elevation of the device,

Figure 2 isan edge view with parts in section.

Referring more particularly to the drawings I have shown the device as comprising a frame which is of the same general shape provided for ordina hack saws and which is formed at one en with an extension 11 defining a handle 12. The main portion of the frame includes front and rear arms 13 and 14 and the handle portion includes an element 15 secured to the arm 14. For convenience in handling, I may also provide a handle 16 secured upon the center of the main frame so as to facilitate guiding or lifting the device.

Secured upon the extension 11 is an electric motor 17 of some suitable construction having its shaft 18 carrying a disk 19 equipped with a wrist pin 20. This constitutes the driving mechanism.

Carried by the frame 10 at a point spaced from the arm 13 is a support 21 through which is slidable a bar 22 having the usual pin 23 upon which the hole at one end of a hack saw blade 24 may be engaged. Slidable through the arm 14 is a similar bar 25 carr in a pin 26 on which the other end of the la e is engaged, the purpose of this particular arrangement being to permit changing blades when necessary.

Pivotally connected with the wrist pin is a pitman or link 27 which is pivotally connected with the rear end of the bar so that when the motor is operated the bar 25 and consequently the hack saw blade will be reciprocated.

An important feature is'the provision of a tension spring 28 which is connected with the bar 22 and with an adjusting screw 29 threaded through the arm 13.

In the operation it will be apparent that when the motor is in action, the blade 24 will be reciprocated rapidly with a very short stroke. Vhen sawing, it is intended that the operator move the entire device slowly so that all portions of the blade will be caused to act upon the material being out. The reason for this is to avoid overheating the blade and to make the wear thereon uniform. As a matter of fact the manual offort involved is very slight so that very rapid and ciiicient work may be done with the utmost case.

While I have shown and described the preferred embodiment of my invention it is of course to be understood that I reserve the right to make such changes in the form, construction and arrangement of parts as will not depart from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention I claim:

1. A device of the character described comprising a frame including spaced arms and having an extension terminating in a. handle, a motor mounted on the extension and having its shaft carrying a disk equipped with a wrist pin, bars slidable through the frame and formed for detachable connection of a saw blade therebetween, and a ped with a wrist pin, bars slidable through pitmanconnected with one bar and with the frame and formed for detachable conll said wrist pin. nection of a saw blade therebetween, and a 2. A device of the character described pitman connected with one bar and with 5 comprising a frame including spaced arms said wrist pin, and ad'ustable spring means and having an-extension terminating in a opposing movement 0 the blade in one dihandle, a motor mounted on the extension rection. and having its shaft carrying a disk equip- DODLEY H. POWELL. 

